In the diploma thesis the accuracy of measurements on permanent sample plots in the forest management unit Jurjeva dolina is estimated. The data of first measuring were taken in 2009 and these data have been used for the management plan of the forest management unit Jurjeva dolina until 2019. Recording leaflets, maps and GPS device were used for our efficient work in the forest. We have taken measurements of 436 sampling plots on 100 x 100 m, 125 x 200 m and 200 x 250 m sampling grid. The accuracy of plot center positions from year 1999 was assessed by GPS technology. Most of the deviations between the measured and exact positions were less than 20 meters.